Fish and shellfish are cellular tissue laden organisms having a genetic code for each aquatic species, and within each species and wide variety of specimen types. Within these genetic codes are variations or alterations which affect growth rates, yield and disease resistance.
Fish and shellfish provide a large source of food. This source of food historically came from fresh water lakes, streams and ponds and from salt water seas and oceans. Fishing was an industry primarily involved in catching large quantities of fish usually by nets cast over ships and drawn into fishing vessels which have a complete processing plant on board. These highly efficient vessels have led to over fishing of some aquatic species.
This combined with disease and other stresses put on marine life have put this primary source of food supply for many people at risk.
Efforts to control the damaging effects of pollutants are being made. Regulations controlling open water fishing are being passed. Nevertheless the growing world population will be consuming more food putting additional stress on marine life absent efforts to increase productivity of these aquatic life forms.
Far more urgent than energy supplies, the human demands and needs for clean potable drinking water are going to be the primary concern with reliable food supplies being a close second in relative importance.
Accordingly improving the yields of quality seafood is an urgent need and integral part of maintaining and meeting man's need for food.
Fish farming and aquaculture or mariculture activities are being increasingly used. In the species of fish known as catfish most are produced from fish farms. These are highly efficient ways to bring fresh fish reliably to market. Other fish types are also similarly being harvested in large quantities from such farms or fisheries. The advantage of such farms is the survival rate of the vast quantities of fish embryos is vastly improved. In the wild or nature most aquatic embryos and small larvae are simply food for predator fish. Whereas in controlled fish farms or fisheries the mortality rate is greatly reduced if the conditions are properly maintained by avoiding stress on the hatchery population and exposure to infectious diseases. Compared to natural risks survival rates are in the 100 fold to 1000 fold better in these controlled conditions albeit the risk of being a human's food is elevated to a 100 percent certainty.
Similarly advances in the harvesting of shellfish are being made in large aquaculture farms. Shrimp which is consumed at a rate of over 1.27 million tons per year are also being grown in large aqua farms. Shrimp production in millions of tons may seem huge, but when compared to fish production it is a tiny fraction of that total.
Crabs, lobsters, clams, scallops, mussels, abalone and other crustaceans can similarly be harvested in such farms.
With such highly efficient production means to grow and harvest marine life it would seem the need to open water fish would become unnecessary and cost prohibitive. The reality is such controlled fisheries and aqua farming activities are so concentrated that the exposure to microbial infections and viruses becomes a huge risk factor. Instead of losing a single school of fish to such an infection in open waters, these concentrated farms risk losing entire populations of production in many cases causing a complete shut down of hatchery operations until the epidemic can be eradicated.
U.S. patent publication US 2005/0158326 A1 entitled “Compositions for Reducing Virus Infection Rate in Aquatic Crustaceans and Applications Thereof” recites: There are about 20 viruses known to be highly pathogenic to shrimps, for example: infectious hypodermal hematopoietic necrosis virus (IHHNV), baculovirus penaei (BP), baculoviral midgut GI and necrosis virus (BMN), monodon baculovirus (MBV), hepatopancreatic parvo-like virus (HPV), reo-like virus, Taura syndrome virus, yellow head virus (YHV), white spot syndrome virus (WSSV) and so on. However, these diseases cannot be treated by the known medication such as copper sulfate, potassium permanganate, formalin, malachite green, oxytetracycline, iodoform 1-500, furyl drug, or sulfa drugs. In addition, there are problems of drug residue and drug resistance with the abovementioned drugs. And the infected shrimps are frequently detected with two or more than two viruses, the so-called “mixed infection”. This situation makes the virus control of shrimps even more complicated and difficult (Diseases of Aquatic Organisms, 48, p 233-236, 2002; Fish Pathology, 35(1), 1-10, 2000; Fish Pathology 24(2), p 89-100, 1989).
A primary object of US 2005/0158326 A1 is to provide a composition for prevention and/or treatment of viral infection in order to control virus infection rates in crustaceans. The composition comprises at least one of the antibodies selected from the group consisting of monoclonal antibody, phage display antibody and antibody produced by a recombinant organism, which can bind specifically to virus. Said composition can be applied in preparation of medicine composition, nutrition composition, feed additives or feed composition.
In U.S. Pat. No. 6,705,556 B2 Charles Rolland Laramore suggests making shrimp as well as other crustaceans tolerant or immune from viral infections by exposing larval shrimp to tolerine compositions. Tolerine compositions are based on inactivated viral-particles which are taken from infected tissue ground up and made into or mixed with a nutrient upon which the shrimp larvae feed.
U.S. Pat. No. 6,692,557 teaches coating the shells of scallops, oysters, mussels or abalones with an antifouling coating composition to a shell will prevent fouling. This solution eliminates the need to periodically clean these shellfish. Fouling or biofouling is when unwanted sediment and growth of marine organisms occurs on the shells. These shellfish have a world wide market of over $6.8 billion dollars and fouling alone is a cost of about 3-7% of that total revenue that would otherwise be profit for the industry.
In US 2004/0253580 A1 an infectious salmon anaemia virus vaccine (ISAV) is proposed to immunize Atlantic salmon from this viral disease. A viral genome was found which encodes a novel viral protein suitable as a vaccine component for fighting ISAV.
Similarly in US 2004/0101929 A1 entitled “Expressing Mammalian Protein Complexes in Fish”, it is stated there is a need to generate fish that are capable of expressing mammalian protein complexes. They report, for example, infectious diseases are common on fish farms due to intensive fish farming that facilitates the transmission of pathogens in an aqueous environment. By binding to pathogens, antibodies inactivate them and therefore protect fish from infectious diseases. In teleost fish, only two types of antibodies, IgM and IgD, have been found. IgM, the major isotype, binds to and inactivates pathogens. However, the efficacy is not satisfactory due to relatively low binding affinity. Expressing mammalian antibodies in fish has several advantages in preventing the fish from infectious diseases. First, antibodies with high affinity can be made using the mammalian hybridoma technology. In addition, genes encoding the antibodies can be introduced into germ-line cells of fish, and transmitted to and expressed in the progenies of the fish. Further, the expressed antibodies can protect the fish progenies during their early stage of development, when the immune system has not fully developed.
Lorenzen reported expressing mammalian single-chain antibodies in fish cells (Nat. Biotechnol. 18:1177-1180, 2000). The single-chain antibodies each contain a single hybrid polypeptide chain having a constant region of an Ig kappa chain, and variable regions of heavy and light chains. As these single-chain antibodies are not stable, they only offer limited protection.
Their invention features a fish cell expressing a mammalian protein complex having two peptide species. The fish cell contains a first nucleic acid sequence encoding a first peptide species of a mammalian protein complex, and a second nucleic acid sequence encoding a second peptide species of the mammalian protein complex. In the fish cell, a multiplicity of peptides of both peptide species are expressed, and at least one peptide of the first peptide species and at least one peptide of the second peptide species assembly to form a functional complex, i.e., a complex capable of performing the task of a naturally occurring protein complex.
The fish cell can be prepared from cells of different tissues (e.g., brain), of various fish such as yellow grouper. The above-mentioned protein complex consists of, e.g., one to four subunits of each of the two peptide species. An example of such a mammalian protein complex is a mammalian antibody, i.e., an immunoglobulin (Ig) having two heavy chains and two light chains, optionally containing a disulfide bond. In one embodiment, a functional antibody specifically binds to a microorganism, e.g., a virus, a bacterium, a protozoan, or a parasite. Another example of a mammalian protein complex is a mammalian signaling molecule, such as a cytokine or a growth factor. A signaling molecule binds to its receptor on a cell and triggers a cellular response. An interlukin, a cytokine, contains only two subunits of two different peptide species.
All of these prior art approaches suggest incorporating a vaccine, antibody or genetically modifying the aquatic life form in some fashion to improve disease resistance. Most involve introducing that modification into the food supply that will later be consumed. This may be quite safe; however, it should raise some concerns about long term health effects. Hopefully these wide scale genetic alterations prove to have no harmful unforeseen effects.
Besides infections the next or most relevant factor in fish farming is growth rate and yield. This relates to the time between embryonic existence to harvest and the size or weight achieved at harvest. Both of these factors determine to a large extent profitability. If one set of aquatic life forms be it fish or shellfish can grow faster or during the time to mature can increase more in size and weight for a give amount of nutrients then the operation will increase revenues without increasing costs.
US 2004/0055029 teaches selectively finding purebred fish and selecting a DNA fingerprint to identify breeder fish to achieve this goal.
U.S. Pat. No. 6,789,502 suggests a method for producing prey organisms enriched in highly unsaturated fatty acids (HUFAs), particularly docosahexaenoic acid (DHA). Also provided are feed compositions based on such organisms.
In a first aspect, the invention provided a method of producing prey organisms for use in aquaculture, in particular for feeding larval fish, the method comprising cultivating said organisms during at least part of their life cycle in an aqueous medium comprising at least one lipid component having a DHA content of at least 30 wt %.
In a further aspect, the invention provided a composition for feeding fish in the larval and/or non-larval stage, the composition comprising the above mentioned prey organisms; said organisms having a content of DHA of at least 12 wt % of the total lipid content of the organisms.
The feed mixture is particularly useful for high demand species such as halibut, trout, salmon and eel.
In US patent 2005/0075587 Robert Vago teaches a novel method of wound cleaning of humans, mammals and fish employing ultrasonic irradiation. In that publication he notes shock wave therapy is not used in that the inherent effects of cavitation can destroy cells and tissue.
The above related findings demonstrate that aquatic life forms like fish and shellfish undergo a systemic response via a form of cross talk or cellular communication. This finding is consistent with a similar cellular communication found in mammals. In each organism be it a fish or mammal, cellular stimulation can result in a release of proteins and other chemical compositions relating to growth factors.
The present invention has the object of stimulating tissue growth and accelerating time to maturation in addition to improving disease resistance which is summarized as follows.